Rigging this mechanical claw. Could do with some help
I'm not a very sophisticated rigger, but this looks to me like a 2-bone IK Chain, like an upper and lower arm.



This is a single armature


B_Susp, B_Pole and B_IK_Tgt are parented to Root
B_Grab has an IK Constraint, target B_IK_Tgt, Pole B_Pole, Length 2, so as to include its immediate parent, B_Susp.
B_IK_Tgt has a Limit Location Bone Constraint in its Local (i.e Root's) space, so it can only move up and down Root's axis, with stops to prevent it from going too far.





Hunks of mesh are directly (Bone-Parent) parented to the bones:


The Cylinder to Root, its Piston to B_IK_Tgt, The Suspension Arm to B_Susp, and the actual Claw to B_Grab.

Once one arm of the claw is working, B_Grab, B_Susp, and B_Pole can be duplicated and rotated 120 degrees around the Root Axis in (Armature) Edit Mode. This may throw their roll .. ShiftN Recalculate Roll on X-tangent fixed it for me. My first arm was constructed Z-up, in front view.

The meshes can be AltD instanced round to follow, and re-parented to their respective bones.

I'm sure someone knows a way of taking the bones and meshes round together.. maybe they can suggest that, or an altogether better way.



As I said, I'm no expert in the bureaucracy of locking rigs down properly, creating good interfaces for animators, etc, but perhaps this is enough for a mechanism that works.